The present invention relates generally to gas turbine engines, and more particularly to an integrated case and stator vane component in a low pressure turbine of a gas turbine engine.
A gas turbine engine typically includes a high pressure spool, a combustion system and a low pressure spool disposed within an engine case to form a generally axial, serial flow path about the engine centerline. The high pressure spool includes a high pressure turbine, a high pressure shaft extending axially forward from the high pressure turbine, and a high pressure compressor connected to a forward end of the high pressure shaft. The low pressure spool includes a low pressure turbine, which is disposed downstream of the high pressure turbine, a low pressure shaft, which typically extends coaxially through the high pressure shaft, and a low pressure compressor connected to a forward end of the low pressure shaft, forward of the high pressure compressor. The combustion system is disposed between the high pressure compressor and the high pressure turbine and receives compressed air from the compressors and fuel provided by a fuel injection system. A combustion process is carried out within the combustion system to produce high energy gases to produce thrust and turn the high and low pressure turbines, which drive the compressors to sustain the combustion process.
Compressors and turbines are comprised of alternating stages of blades and vanes that are arranged radially around a center axis of the engine within the axial flow path of the engine case. For example, in the low pressure turbine, blades are connected to the low pressure shaft such that they rotate about the engine centerline, while vanes are supported by the engine case such that they remain stationary between the blades. Traditionally, the hooks have been used to attach vanes individually or in small clusters. Not only do these hooks provide thermal mechanical fatigue and low cycle fatigue cracking areas due to the complex machined features, but the gaps between the vanes or vane clusters provide leakage pathways that can lower engine efficiency and can cause thermal hot-spots on the engine case.